/*
 * Copyright 2007 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*namespace com.google.zxing.common {*/

import BitMatrix from './BitMatrix'
import PerspectiveTransform from './PerspectiveTransform'
import Exception from './../Exception'

/**
 * Implementations of this class can, given locations of finder patterns for a QR code in an
 * image, sample the right points in the image to reconstruct the QR code, accounting for
 * perspective distortion. It is abstracted since it is relatively expensive and should be allowed
 * to take advantage of platform-specific optimized implementations, like Sun's Java Advanced
 * Imaging library, but which may not be available in other environments such as J2ME, and vice
 * versa.
 *
 * The implementation used can be controlled by calling {@link #setGridSampler(GridSampler)}
 * with an instance of a class which implements this interface.
 *
 * @author Sean Owen
 */
abstract class GridSampler {

  /**
   * Samples an image for a rectangular matrix of bits of the given dimension. The sampling
   * transformation is determined by the coordinates of 4 points, in the original and transformed
   * image space.
   *
   * @param image image to sample
   * @param dimensionX width of {@link BitMatrix} to sample from image
   * @param dimensionY height of {@link BitMatrix} to sample from image
   * @param p1ToX point 1 preimage X
   * @param p1ToY point 1 preimage Y
   * @param p2ToX point 2 preimage X
   * @param p2ToY point 2 preimage Y
   * @param p3ToX point 3 preimage X
   * @param p3ToY point 3 preimage Y
   * @param p4ToX point 4 preimage X
   * @param p4ToY point 4 preimage Y
   * @param p1FromX point 1 image X
   * @param p1FromY point 1 image Y
   * @param p2FromX point 2 image X
   * @param p2FromY point 2 image Y
   * @param p3FromX point 3 image X
   * @param p3FromY point 3 image Y
   * @param p4FromX point 4 image X
   * @param p4FromY point 4 image Y
   * @return {@link BitMatrix} representing a grid of points sampled from the image within a region
   *   defined by the "from" parameters
   * @throws NotFoundException if image can't be sampled, for example, if the transformation defined
   *   by the given points is invalid or results in sampling outside the image boundaries
   */
  public abstract sampleGrid(image: BitMatrix,
                                      dimensionX: number /*int*/,
                                      dimensionY: number /*int*/,
                                      p1ToX: number/*float*/, p1ToY: number/*float*/,
                                      p2ToX: number/*float*/, p2ToY: number/*float*/,
                                      p3ToX: number/*float*/, p3ToY: number/*float*/,
                                      p4ToX: number/*float*/, p4ToY: number/*float*/,
                                      p1FromX: number/*float*/, p1FromY: number/*float*/,
                                      p2FromX: number/*float*/, p2FromY: number/*float*/,
                                      p3FromX: number/*float*/, p3FromY: number/*float*/,
                                      p4FromX: number/*float*/, p4FromY: number/*float*/): BitMatrix /*throws NotFoundException*/
  
  public abstract sampleGridWithTransform(image: BitMatrix,
                                      dimensionX: number /*int*/,
                                      dimensionY: number /*int*/,
                                      transform: PerspectiveTransform): BitMatrix /*throws NotFoundException*/

  /**
   * <p>Checks a set of points that have been transformed to sample points on an image against
   * the image's dimensions to see if the point are even within the image.</p>
   *
   * <p>This method will actually "nudge" the endpoints back onto the image if they are found to be
   * barely (less than 1 pixel) off the image. This accounts for imperfect detection of finder
   * patterns in an image where the QR Code runs all the way to the image border.</p>
   *
   * <p>For efficiency, the method will check points from either end of the line until one is found
   * to be within the image. Because the set of points are assumed to be linear, this is valid.</p>
   *
   * @param image image into which the points should map
   * @param points actual points in x1,y1,...,xn,yn form
   * @throws NotFoundException if an endpoint is lies outside the image boundaries
   */
  protected static checkAndNudgePoints(image: BitMatrix,
                                            points: Float32Array): void /*throws NotFoundException*/ {
    const width: number /*int*/ = image.getWidth();
    const height: number /*int*/ = image.getHeight();
    // Check and nudge points from start until we see some that are OK:
    let nudged: boolean = true
    for (let offset = 0; offset < points.length && nudged; offset += 2) {
      const x = Math.floor(points[offset])
      const y = Math.floor(points[offset + 1])
      if (x < -1 || x > width || y < -1 || y > height) {
        throw new Exception(Exception.NotFoundException)
      }
      nudged = false
      if (x == -1) {
        points[offset] = 0.0
        nudged = true
      } else if (x == width) {
        points[offset] = width - 1
        nudged = true
      }
      if (y == -1) {
        points[offset + 1] = 0.0
        nudged = true
      } else if (y == height) {
        points[offset + 1] = height - 1
        nudged = true
      }
    }
    // Check and nudge points from end:
    nudged = true
    for (let offset = points.length - 2; offset >= 0 && nudged; offset -= 2) {
      const x = Math.floor(points[offset])
      const y = Math.floor(points[offset + 1])
      if (x < -1 || x > width || y < -1 || y > height) {
        throw new Exception(Exception.NotFoundException)
      }
      nudged = false
      if (x == -1) {
        points[offset] = 0.0
        nudged = true
      } else if (x == width) {
        points[offset] = width - 1
        nudged = true
      }
      if (y == -1) {
        points[offset + 1] = 0.0
        nudged = true
      } else if (y == height) {
        points[offset + 1] = height - 1
        nudged = true
      }
    }
  }

}

export default GridSampler